From: Felix Fietkau <nbd@openwrt.org>
Date: Mon, 13 Apr 2015 15:56:26 +0200
Subject: [PATCH] bgmac: reset all 4 GMAC cores on init

On a BCM4709 based device, I found that GMAC cores may be enabled at
probe time, but only become usable after a full reset.
Disable cores before re-enabling them to ensure that they are properly
reset.

Signed-off-by: Felix Fietkau <nbd@openwrt.org>
---

--- a/drivers/net/ethernet/broadcom/bgmac.c
+++ b/drivers/net/ethernet/broadcom/bgmac.c
@@ -1623,8 +1623,11 @@ static int bgmac_probe(struct bcma_devic
 			ns_core = bcma_find_core_unit(core->bus,
 						      BCMA_CORE_MAC_GBIT,
 						      ns_gmac);
-			if (ns_core && !bcma_core_is_enabled(ns_core))
-				bcma_core_enable(ns_core, 0);
+			if (!ns_core)
+				continue;
+
+			bcma_core_disable(ns_core, 0);
+			bcma_core_enable(ns_core, 0);
 		}
 	}